Integrated core/casing plate heat exchanger

ABSTRACT

A plate heat exchanger includes a case assembly and a plurality of primary flow channel assemblies. The case assembly includes first and second side panels and first and second end plates mounted to the ends of the side plates. Each of the end plates has alternating slots, and ribs extending transversely between the laterally extending edges of the end plate, with the slots of the first end plate and corresponding slots of the second end plate defining multiple pairs of slots. Each primary flow channel assembly includes laterally spaced first and second heat exchange plates, with the inner surfaces of the heat exchange plates forming a longitudinally extending primary flow passage. One of the primary flow channel assemblies is associated with each pair of slots with a first end portion of the flow channel assembly mounted in the slot of the first end plate and the second end portion of the flow channel assembly mounted in the corresponding slot of the second end plate. Transversely extending secondary flow passages are formed between the outer surfaces of the heat exchange plates of adjacent primary flow channel assemblies.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to recuperative heat exchangers. More particularly, the present invention relates to recuperative heat exchangers having plate structures adapted to transfer heat from one fluid to another through the surface of the plate.

[0002] Recuperative heat exchangers are known in which a plurality of plates of relatively thin material are stacked in face-to-face arrangement to define fluid passages therebetween for separate flow of primary and secondary fluids in the heat exchange relation. A thin plate type of heat exchanger has been generally very difficult to manufacture, due to the many welding and bonding operations required, and difficult to achieve a strong structure because of the thinness of the plate material. Typically, the heat transfer plates are stacked horizontally on the shop floor and either welded or clamped to form a core having alternating primary and secondary flow paths. After assembly of the core is completed, a casing is constructed around it. Then the gaps between the casing and the core are closed using one of numerous traditional sealing designs. These seals function to prevent leakage between the primary and secondary sides of the heat exchanger.

[0003] There are several problems with this traditional method of manufacture. First, the construction and manufacturing of the traditional sealing systems is labor intensive. The core and the casing experience differential thermal growth in all three dimensions. Such differential thermal growth commonly results in failure of the seals, since the seals are conventionally fixed to both the core and the casing. Three of the four corners of the core generally have an irregular shape due to variances in the plate dimensions. These corners provide a poor surface for seals to contact and/or a difficult surface to interface with other parts. Traditionally, the plates are not thick enough to prevent deformation when stacked horizontally. Spacing devices, such as pins, are required to maintain the plate-to-plate distances during stack-up. These pins account for unnecessary assembly man-hours.

SUMMARY OF THE INVENTION

[0004] Briefly stated, the invention in a preferred form is an integrated core/casing plate heat exchanger which comprises a case assembly and a plurality of primary flow channel assemblies. The case assembly includes first and second side panels, each of which has longitudinally extending first and second edges and first and second ends. A first end plate is mounted to the first ends of the first and second side plates and a second end plate is mounted to the second ends of the first and second side panels. Each of the end plates having laterally extending first and second edges and first and second sides. The end plates have multiple slots, with each of the slots being separated from an adjacent slot by a rib. The slots and the ribs of each plate extending transversely between the laterally extending edges of the end plate. The second end plate has a corresponding slot and rib for each slot and rib of the first end plate, with the slots of the first end plate and the corresponding slots of the second end plate each defining a pair of slots. Each primary flow channel assembly includes laterally spaced first and second heat exchange plates. The inner surfaces of the first and second heat exchange plates form a longitudinally extending primary flow passage. One of the primary flow channel assemblies is associated with each pair of slots with a first end portion of the flow channel assembly mounted in the slot of the first end plate and the second end portion of the flow channel assembly mounted in the corresponding slot of the second end plate. The outer surfaces of the heat exchange plates of one primary flow channel assembly forming transversely extending secondary flow passages with the outer surfaces of the heat exchange plates of adjacent primary flow channel assemblies.

[0005] Each side panel includes a sheet member and multiple stiffening members, with the stiffening members being mounted to the outer surface of the sheet member. The stiffening members include multiple transverse stiffening members and multiple longitudinal stiffening members. The inner surface of the sheet member of each side panel defines a transversely extending, secondary flow passage with the outer surface of the heat exchange plate of an adjacent primary flow channel.

[0006] The heat exchanger further comprises first and second edge flange assemblies mounted to the first and second edges of the side panels and the first and second edges of the end plates. First and second end flange assemblies are mounted to the first and second ends of the side panels and/or the outer faces of the first and second end plates.

[0007] It is an object of the invention to provide a plate heat exchanger which does not require seals between core and the sides of the heat exchanger.

[0008] It is also an object of the invention to provide a plate heat exchanger which does not require the placement of spacers between the heat exchange plates during construction of the core.

[0009] Other objects and advantages of the invention will become apparent from the drawings and specification.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings in which:

[0011]FIG. 1 is a perspective view illustrating the assembly of a plate heat exchanger in accordance with the invention;

[0012]FIG. 2 is an exploded view of the case assembly of FIG. 1;

[0013]FIG. 3 is an enlarged front view of a end plate of FIG. 1; and

[0014]FIG. 4 is an exploded view of the primary flow channel assembly of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] With reference to the drawings wherein like numerals represent like parts throughout the several FIGUREs, an integrated core/casing plate heat exchanger in accordance with the present invention is generally designated by the numeral 10. The integrated core/casing plate heat exchanger 10 is comprised of two main components, a case assembly 12 and multiple primary flow channel assemblies 14. To facilitate discussion, the heat exchanger 10 will be described as though the primary flow assemblies 14 extended in a vertical and longitudinal direction, as illustrated in FIG. 1. It should be understood that the heat exchanger 10 may be installed and utilized in any orientation.

[0016] With reference to FIG. 4, each primary flow channel assembly 14 includes first and second heat exchange plates 16, 16′ which are joined longitudinally to create an enclosed, longitudinally extending, primary flow passage 20. Preferably, all of the primary flow channel assemblies 14 in an heat exchanger 10 are substantially identical. For the flat heat exchange plates 16, 16′ illustrated in FIG. 4, a pair of edge bars 22, 24 are required to establish the gap between the heat exchange plates 16, 16′ which forms the primary flow passage 20. The top edge bar 22 is positioned between the top portions 26 of the heat exchange plates 16, 16′ and the bottom edge bar 24 is positioned between the bottom portions 28 of the heat exchange plates 16, 16′, with the primary flow passage 20 being defined by the cavity formed between the edge bars 22, 24 and the primary surfaces 30 of the heat exchange plates 16, 16′. Preferably, the edge bars 22, 24 extend the full longitudinal length of the heat exchange plates 16, 16′ and the edge bars 22, 24 are welded along their full length to the heat exchange plates 16, 16′ to form an enclosed primary flow passage 20. For formed heat exchange plates, edge bars and welding may not be required.

[0017] With reference to FIGS. 2 and 3, the case assembly 12 includes substantially identical, first and second side panels 32, 32′ which are disposed on opposite sides of the heat exchanger 10. Each side panel 32, 32′ includes a sheet member 34 and multiple stiffening members 36, 36′. The inner surface 38 of each sheet member 34 forms one side of a secondary flow passage 40, as described in more detail below. The stiffening members, including multiple vertical stiffening members 36 and multiple horizontal stiffening members 36′, are welded to the outer surface 42 of the sheet member 34, providing sufficient mechanical strength to the side panels 32, 32′ to support the weight of the other case assembly components and the primary flow channel assemblies 14.

[0018] Substantially identical, first and second end plates 44, 44′ are mounted to the opposite ends of the side panels 32, 32′, preferably by welding. With reference to FIG. 3, each end plate 44, 44′ has multiple slots 46, with each of the slots 46 being separated from an adjacent slot 46′ by a rib 48 of the plate material, the slots 46 and ribs 48 extending transversely between the laterally extending upper and lower edges of the end plates 44, 44′. The second end plate 44′ has a corresponding slot 46 and rib 48 for each slot 46 and rib 48 of the first end plate 44. The width 50 and height 52 of the slots 46 are selected to facilitate insertion of a primary flow channel assembly 14 there through. The majority of the secondary flow passages 40 of the heat exchanger 10 are defined by corresponding ribs 48 of the first and second end plates 44, 44′ and the secondary surfaces 54 of the heat exchange plates 16, 16′ of the primary flow channel assemblies 14 mounted within the slots 46 on either side of the corresponding ribs 48. Two secondary flow passages 40 are defined by the inner surfaces 38 of sheet members 34, the secondary surfaces 54 of primary flow channel assemblies 14 mounted within the two laterally outer slots 46, 46″, and the side portions 56, 56′ of the end plates 44, 44′. The width 58 of the ribs 48 and the width 60 of the side portions 56, 56′ are selected on the basis of the required dimensions for the secondary flow passages 40. The total number of slots 46 is determined by the required number of heat exchange plates 16, 16′ in the heat exchanger 10.

[0019] Upper and lower flange assemblies 62, 64 are mounted, preferably by welding, to the upper and lower edges 66, 68, respectively, of the side panels 32, 32′ and the end plates 44, 44′. First and second end flange assemblies 70, 72 are mounted, preferably by welding, to the first and second ends 74, 76 of the side panels 32, 32′ and/or the outer faces 78 of the first and second end plates 44, 44′. The flange assemblies 62, 64, 70, 72 provide a flush surface by which the heat exchanger 10 may be connected to the ductwork (not shown) for transporting the primary and secondary fluids.

[0020] With further reference to FIG. 1, the heat exchanger 10 is assembled by orienting a case assembly 12 such that the end plate slots 46 extend in a vertical direction. Consecutively, a primary flow channel assembly 14 is inserted through each slot 46 on the first end plate 44 until the distal end portion 80 of the primary flow channel assembly 14 is received in the corresponding slot 46 of the second end plate 44′.

[0021] After each pair of slots 46 has been filled with a primary flow channel assembly 14, the proximal end portions 82 are welded to the first end plate 44 and the distal end portions 80 are welded to the second end plate 44′, leaving the proximal and distal ends 84, 86 of the primary flow passages 20 open to allow the primary fluid to flow longitudinally through the heat exchanger 10. Variations in the longitudinal lengths of the primary flow channel assemblies 14 may be accounted for by the welding procedure. The vertically extending secondary flow passages 40 allow the secondary fluid to flow laterally through the heat exchanger 10.

[0022] It should be appreciated that the subject heat exchanger 10 integrates the core and the casing into a single assembly, eliminating the requirement for a sealing system. This reduces the time required to manufacture the heat exchanger 10 and provides increased reliability of the heat exchanger 10 with respect to leakage. The configuration of the slotted end plate 44, 44′ allows the installation of the primary flow channel assemblies 14 in an upright orientation, as opposed to horizontal. This simplifies handling of the heat exchange plates 16, 16′ and eliminates the need for inter-channel spacers. The tolerance on the heat exchange plate dimensions is also made less sensitive because the end portions 80, 82 of the primary flow channel assemblies 14 may extend through the slots 46. Variance in the heat exchange plate widths may be easily compensated for in the weld procedure.

[0023] While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation. 

What is claimed is:
 1. An integrated core/casing plate heat exchanger comprises: a case assembly including oppositely disposed first and second side panels, each of the side panels having oppositely disposed longitudinally extending first and second edges and oppositely disposed first and second ends, and first and second end plates, the first end plate being mounted to the first ends of the first and second side panels and the second end plate being mounted to the second ends of the first and second side panels, each of the end plates having an outer face, oppositely disposed, laterally extending first and second edges, and oppositely disposed first and second sides, the first and second end plates defining a plurality of slots, each of the slots being separated from an adjacent slot by a rib, the slots and the ribs of each plate extending transversely between the laterally extending edges of the end plate, the second end plate having a corresponding slot and rib for each slot and rib of the first end plate, the slots of the first end plate and the corresponding slots of the second end plate each defining a pair of slots; and a plurality of primary flow channel assemblies, a one of the primary flow channel assemblies being associated with each pair of slots, each primary flow channel assembly including longitudinally separated first and second end portions and laterally spaced, first and second heat exchange plates, each of the heat exchange plates having inner and outer surfaces, the inner surfaces of the first and second heat exchange plates defining a longitudinally extending primary flow passage therebetween, the first end portion of the flow channel assembly being mounted in the slot of the first end plate and the second end portion of the flow channel assembly being mounted in the corresponding slot of the second end plate, the outer surface of the first heat exchange plate of the primary flow channel assembly defining a transversely extending, inner secondary flow passage with the outer surface of the second heat exchange plate of an adjacent primary flow channel assembly.
 2. The heat exchanger of claim 1 wherein each of the slots of each end plate has a width and height selected to facilitate insertion of a primary flow channel assembly therethrough.
 3. The heat exchanger of claim 1 wherein each side panel includes a sheet member and a plurality of stiffening members, the sheet member having oppositely disposed inner and outer surfaces, the stiffening members being mounted to the outer surface of the sheet member.
 4. The heat exchanger of claim 3 wherein the stiffening members include a plurality of transverse stiffening members and a plurality of longitudinal stiffening members.
 5. The heat exchanger of claim 3 wherein the inner surface of the sheet member of each side panel defines a transversely extending, outer secondary flow passage with the outer surface of a one of the heat exchange plates of an adjacent primary flow channel.
 6. The heat exchanger of claim 1 further comprising first and second edge flange assemblies mounted to the first and second edges, respectively, of the side panels and the first and second edges, respectively, of the end plates.
 7. The heat exchanger of claim 6 further comprising first and second end flange assemblies mounted to the first and second ends of the side panels
 8. The heat exchanger of claim 6 further comprising first and second end flange assemblies mounted to the first and second ends of the side panels and the outer faces of the first and second end plates.
 9. The heat exchanger of claim 6 further comprising first and second end flange assemblies mounted to the outer faces of the first and second end plates.
 10. The heat exchanger of claim 1 wherein each primary flow channel assembly also includes transversely separated, longitudinally extending first and second edge bars mounted to the first and second heat exchange plates proximate to the first and second edges of the primary flow channel.
 11. An integrated core/casing plate heat exchanger comprises: a case assembly including oppositely disposed first and second side panels, each of the side panels having oppositely disposed longitudinally extending first and second edges, oppositely disposed first and second ends, a sheet member and a plurality of stiffening members, the sheet member having oppositely disposed inner and outer surfaces, the stiffening members being mounted to the outer surface of the sheet member, and first and second end plates, the first end plate being mounted to the first ends of the first and second side panels and the second end plate being mounted to the second ends of the first and second side panels, each of the end plates having an outer face, oppositely disposed, laterally extending first and second edges, and oppositely disposed first and second sides, the first and second end plates defining a plurality of slots, each of the slots being separated from an adjacent slot by a rib, the slots and the ribs of each plate extending transversely between the laterally extending edges of the end plate, the second end plate having a corresponding slot and rib for each slot and rib of the first end plate, the slots of the first end plate and the corresponding slots of the second end plate each defining a pair of slots; first and second edge flange assemblies mounted to the first and second edges of the side panels and the first and second edges of the end plates, respectively; first and second end flange assemblies mounted to the first and second ends of the side panels or the outer faces of the first and second end plates; and a plurality of primary flow channel assemblies, a one of the primary flow channel assemblies being associated with each pair of slots, each primary flow channel assembly including longitudinally separated first and second end portions and laterally spaced, first and second heat exchange plates, each of the heat exchange plates having inner and outer surfaces, the inner surfaces of the first and second heat exchange plates defining a longitudinally extending primary flow passage therebetween, the first end portion of the flow channel assembly being mounted in the slot of the first end plate and the second end portion of the flow channel assembly being mounted in the corresponding slot of the second end plate, the outer surface of the first heat exchange plate of the primary flow channel assembly defining a transversely extending, inner secondary flow passage with the outer surface of the second heat exchange plate of an adjacent primary flow channel assembly; wherein the inner surface of the sheet member of each side panel defines a transversely extending, outer secondary flow passage with the outer surface of a one of the heat exchange plates of an adjacent primary flow channel. 